Electrode for lightning-arresters.



PATENTED AUG. 25, 1908.

F. B. COOK. ELECTRODE FOR LIGHTNING ARRESTERS.

APPLIUATION FILED NOV. 27, 1907.

win-ruse: :s

a rar ng o oorrpor 'i wqrsqh 1 i a ma ian i 'Applicationillodli'ovembsrfl,1907- 8erla1 No.'404,1:2 'l.- f;,;

To allwhom'itmay concern:

Be it known that I, FRANK 'B. Coox, a citizen of the United States-of America, residing at Chicago, in the county of Cook andState of IlllIlOlS, have invented new and useful Electrodes for Lightnirig-Arresters, of which the following is a speci cation, reference being had to the accompanying drawings, illustrating same. s

My invention relates to high potential electricity arresters, and more particularly electrodes of the arresters as well as the imelectrodes 'were coated with an insulating material such as shellac, the said insulating coating serving as the dielectric between the electrodes to normally hold the latter apart and out of electrical connection with each other; This form of coating for the active surfaces of the electrodes is objectionablein certainelectricalfsystems, such as tele hone systems, where the voltage on which t 0 armeter is sup osed to cause a discharge to take place t erethrough is comparatively low, generally about 500 volts, because it takes a ver high voltage to puncture the shellac if t e latter is put on sufficiently thick to properly insulate the electrodes from each other under normal conditions. I

. am also aware that electrodes of lightning about 30 minutes, dryin arresters have been impregnated with a binding material and then the active surfaces of the electrodes ground off to remove the film of binding material and present a rough active surface, the entire process consisting of immersing the carbon electrodes in a hot solution of the binding material for about 24 hours, then grin ing the active surfaces of the carbons, washing the latter in water and then again drying them. One disadvantage in this treatment is the length the carbons for oftime' required and: the expense necessarili incurred i'nthus treating the electrodes. still further objection is that the active surfaces of the electrodes, being ground off after the electrodes are impregnated. with the binding material, are rough andtherefore provide numerous indentures therein which may readil fill up with carbon dust or for-- eign partic es, in handling, shipping, or utilizlng the arresters, practically the same as in t e ordinary carbon electrodes which are not treated in any manner but merely washed and thoroughly cleaned in the beginning.

In my present invention I treat the active surfaces of the electrodes of high-potential electricity arresters'with a non-conducting adhesive material, preferably a cement, the body of which is celluloid, which is a plied to the said active surfaces so as to mere y fill up the indentures or low places in; the said sur- Specification or man Pa e; re t a aid-190 85} faces and leave the high points of the said surfaces exposed. This provides a smooth active surface for each electrode, which sur face has no indentures therem .to collect or hold carbon dust or foreign particles andwhich at the same time has a reat number of exposed points from which t e discharges This coat- 1 take place through the arrester. ing does not form a dielectric to hold the electrodes out of electrical connection with each other, and therefore does not require a materially higher voltage to are through the arrester than through a similar arrester in which the active surfaces are not treated with the nonconducting material. This coating being in the form of a cement holds the particles of a carbon electrode together and therefore prevents them from breaking off during the use-of the arrester. The celluloid ash being'a nonconductor does not form a lowresistance path through the arrester even after a severe dischargpltherethrough.

In the process w 'ch Iiemploy for treating the electrodes of this invention the non-- conducting binding material or cement is applied to the active surfaces of the electrodes- With a brush and then wiped smoothly with a cloth before it has time to dry to any considerable extent. This process provides a very thin and uniform coating for the active surfaces of the electrodes, It can be readily seen that this process of treating the electrodes is a very simple one.

In the accom anying drawings, Figure 1 illustrates a big potential electricity arv rester in which the electrodes are treated aecordin to my present invention; Fig. 2 shows a suita ble dielectric to be used'between the electrodes of the arrester shown in Fig. 1 and Fig. 3 is a erspective view of one of the electrodes of the arrester of Fig. 1 treated by the process of this invention.

Like characters refer---to like parts in the several figures.

1 l are the carbon electrodes of the arrester illustrated. Each electrode 1 is coated on its active surface 2 with the nonconducting adhesive material hereinbefore mentioned. Before applying the coating to the carbon 1 the latter is first thoroughly cleaned. Then the coating is applied with a brush after which the active surface 2 is wiped with a cloth to remove all of the coating except a very thin film thereof. This nonconducting material is also preferably applied to the sides of the carbon 1 as at 3 3, preferably as shown, so as to insulate the sides of the electrode adjacent to the active surface 2 thereof from foreign particles or objects, the said material being applied here thicker than on the active surface 2, so as to thoroughly insulate the side portions 3 3 back from the dielectric 4, as shown in Fig. 1.

I do not wish to limit this inventlon to all of the particular details herein described, as various departures therefrom may be made without departing from the scope of the appended claims.

Having thus I claim is:

1. An electrode for a high-potential elecdescribed my invention, what I tricity arrester, comprising a carbon block having nonconductin adhesive material applied to the active su ace thereof so as to exose only the high portions of said active surace. I

2. An electrode for a high-potential electricity arrester, comprising a conductive portion having a rough active surface, and nonconductlng adhesive material applied to the said active surface so .as to leave only the high portions of said surface exposed.

3. A carbon'electrode for a highotential electricity arrester, having a roug active surface, and nonconducting adhesive material ap lied to the said active surface to fill up the ow portions of said surface and leave the high portions of said surface exposed.

4. An electrode for a high-potential electricity arrester, com rising a conductive portion the active suI ace of which is treated with a nonconducting adhesive material containing celluloid.

5. An electrode for a high-potential electricity arrester, comprising a piece of carbon the active surface of which is treated with a noneonducting adhesive material the body of which is celluloid.

6. An electrode for a high-potential electricity arrester, comprising a carbon block the active surface of which is treated with a nonconducting adhesive material the body of which is celluloid, so as to leave only the high points of said active surface exposed.

As inventor of the foregoing I hereunto subscribe my name in the presence of two subscribing witnesses, this 22nd day of November, 1907.

FRANK B. COOK.

Witnesses FREDERICK R. PARKER, C. O. NEWBURN. 

